标签归档：cursor: pin S wait on X undo$

oracle open hang 等待cursor: pin S wait on X

发表于 2022 年 10 月 18 日 由 惜分飞

客户19.3数据库无法在open过程hang住
20221018151321

分析alert日志

2022-10-18T15:04:57.374918+08:00
db_recovery_file_dest_size of 102400 MB is 9.58% used. This is a
user-specified limit on the amount of space that will be used by this
database for recovery-related files, and does not reflect the amount of
space available in the underlying filesystem or ASM diskgroup.
2022-10-18T15:09:55.535116+08:00
ORCLPDB(4):>>> WAITED TOO LONG FOR A ROW CACHE ENQUEUE LOCK! pid=40
ORCLPDB(4):System State dumped to trace file /data/app/oracle/diag/rdbms/orcl/orcl/trace/orcl_p000_31225.trc
2022-10-18T15:19:33.374783+08:00
ORCLPDB(4):Undo initialization recovery: err:1013 start: 1911760 end: 2790176 diff: 878416 ms (878.4 seconds)
Pdb ORCLPDB hit error 1013 during open read write (1) and will be closed.

这里比较明显,cdb本身open正常,但是其中的ORCLPDB这个pdb无法open,从而显示hang的情况.查询数据库会话情况

SQL> select event,sql_id from v$session where wait_class#<>6;

EVENT								 SQL_ID
---------------------------------------------------------------- -------------
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh

EVENT								 SQL_ID
---------------------------------------------------------------- -------------
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
row cache lock							 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
SQL*Net message to client					 1dhc13tspcmys
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh

EVENT								 SQL_ID
---------------------------------------------------------------- -------------
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh
cursor: pin S wait on X 					 8vyjutx6hg3wh

33 rows selected.

SQL> select sql_text from v$sql where sql_id='8vyjutx6hg3wh';

SQL_TEXT
--------------------------------------------------------------------------------
update /*+ rule */ undo$ set name=:2,file#=:3,block#=:4,status$=:5,user#=:6,undo
sqn=:7,xactsqn=:8,scnbas=:9,scnwrp=:10,inst#=:11,ts#=:12,spare1=:13 where us#=:1

SQL> col machine for a30
SQL> /

   INST_ID	  SID PADDR	       SQL_ID	     EVENT			    MACHINE	 PROGRAM
---------- ---------- ---------------- ------------- ------------------------------ ------------ ------------------------
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)

   INST_ID	  SID PADDR	       SQL_ID	     EVENT			    MACHINE	 PROGRAM
---------- ---------- ---------------- ------------- ------------------------------ ------------ -----------------------
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 4517 00000001907FEC50 8vyjutx6hg3wh row cache lock		    xifenfei	 oracle@xifenfei (P000)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)

   INST_ID	  SID PADDR	       SQL_ID	     EVENT			    MACHINE	 PROGRAM
---------- ---------- ---------------- ------------- ------------------------------ ------------ -----------------------
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)
	 1	 5645 000000018095AF40 8vyjutx6hg3wh cursor: pin S wait on X	    xifenfei	 oracle@xifenfei (P002)

31 rows selected.

SQL> l
  1  select b.INST_ID,b.sid,b.paddr,b.sql_id,b.event,b.MACHINE,b.PROGRAM from gv$session a,gv$session b
  2* where a.event='cursor: pin S wait on X'  and a.FINAL_BLOCKING_INSTANCE=b.INST_ID and
  3* a.FINAL_BLOCKING_SESSION=b.sid
SQL>

通过上述分析,可以确认是在open pdb的过程中被cursor: pin S wait on X等待事件阻塞,而被阻塞的sql是update /*+ rule */ undo$ set …………，基于这样的情况.大概率可以确认是由于bug导致.通过查询mos,确认和Bug 30931981 – Open Reset Logs Hangs With ‘row cache lock’ and ‘cursor: pin s wait for x’ Waits (Doc ID 30931981.8)类似.
20221018200418

不过由于客户的版本是19.3,没有对应的小patch发布.通过对相关恢复事务和恢复方式进行处理,在没有对数据库版本进行任何调整的情况下,顺利打开数据库以最快的速度恢复业务
20221018200716
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